How to properly configure a router based on Atom and Ubuntu Server?

Question

ubuntu

All the best!
I started to get acquainted with niks and I liked their stability of work. Now I want to assemble myself a router based on intel atom and ubuntu server. Now I use the "iron router" on openwrt. I understand perfectly well that when building a router for an ubuntu server, I will have to take care of its configuration and security myself. Where can you read examples? I would not want to expose the computer as a bare fifth point in the Internet, especially with a white IP.
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Maybe I didn't choose the right OS for my task. In general, I'm waiting for the amendments.

Answer 1

Where can you read examples?

Instructions on this topic can be found in large quantities by keywords: ubuntu router
Corrections for what?

Answer 2

Iptables is the backbone of *nix routing. Ubuntu Server is suitable as an initial stage (software and manuals for it in bulk). If you focus specifically on routing - FreeBSD.

Answer 3

Well, here are the first problems ((
When I try to switch wlan0 to access point mode with the command sudo iwconfig wlan0 mode Master ,
I get
SET failed on device wlan0 ; Invalid argument .. I tried to give the command sudo ifconfig wlan0
down. It didn’t help.